Will the climate crisis deal the deathblow to glaciers? A study published in Science Thursday, January 5 shows how vulnerable their future is. Almost half of the world’s white giants, or 104,000, are projected to disappear by 2100 even if global warming were limited to 1.5°C compared to the pre-industrial era. This goal, the most ambitious of the Paris Agreement, is is considered unattainable by a growing number of scientists. More than 80% of them would be condemned if mercury levels rose by 4°C, a pessimistic scenario of uncontrolled use of fossil fuels (coal, oil and gas), the main causes of global warming.

This new work, carried out by an international team of scientists, also shows that the world’s 215,000 glaciers – excluding the Greenland and Antarctic ice caps – could lose between 26% and 41% of their mass compared to 2015, depending on the different temperature scenarios. This study is deteriorating previous forecasts that have fueled the particular latest report of the Intergovernmental Panel on Climate Change (IPCC).

“We have observed a linear relationship between global temperature rise and glacial mass loss.states Etienne Berthier, glaciologist (CNRS) at the Laboratory for Space Geophysics and Oceanographic Studies in Toulouse and one of the authors of the study. Each additional fraction of a degree increases ice melting. »

The little ones first

Most of the glaciers whose death is announced for the end of the century are the smallest ones, less than 1 km in area², which actually make up 80% of the total. Scientists say their disappearance will have little impact on sea level rise, but it might “negatively affect the hydrological cycle, tourism, local cultures and glacier-related hazards”, like breakdowns. Glaciers, which play an important role as water towers, help provide water to 1.9 billion people around the world.

If all regions of the world are affected, low and mid-latitude glaciers will be hit the hardest, particularly in central Europe, the Caucasus, Scandinavia, northern Asia, western Canada, and the United States or New Zealand. They should melt sharply from a warming of 2°C and be almost total at + 3°C.

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